M., not sure whether it is acid reflux. I would think by the age of 7-9 months kids outgrow that, but again i am not positive on this.
BUT, i do remmeber my kids before turning 1, the sleep pattern was ...well non existing. I absolutely rejected cry it out for so many reasons, mainly though because i did not have the heart to do that. I read so many books pro and con cry it out and they got me ever more confused. So I sucked it up, up to the point when it did not work anymore. Just couldn;'t go through waking up 5-6 times a night. Around the age of two (i have twins, one was a great sleep the other one was the crier), so, one night, i put the good sleeper to bed kissed and went out. not a peep. i went to the other one and put her in her bed kissed her good night and left. i came into my room turned on the baby monitor and heard her cry. my heart was breaking but unless her cry changed to i am hurting cry i had made up my mind not to go in. i didn't. she cried for 1 hr, or more. but i did not go in. i was told if you wanna to the CIO it will take a few nights to say the least. mine took one night. the next night i did the same thing and she cried for a minute or two and stopped. since then she just slept in her own.
i cannot tell you how much i regretted not doing this long time ago. it was the best thing for her and me. she is 28 months now and sleeps on her own. it's just great. just last night around 10 pm she started crying and i went in which i haven't done before and asked her what was wrong. she gave me this poutty look and didn't say anything. so i got her some water, she drank all of it (she was thirsty i guess) and then said nightey night i love you.
SOOOO bottom line is if it isn't acid reflux (which you might wanna have it checked just in case) then CIO might work for you. doesn't work for every parent and i don't want to start a debate here, i am just telling you my experience.
good luck to you